In need of a little electrical help

DWill · Jan 20, 2020

I want to add a completely separate but redundant float switch/relay to my Tunze Nano ATO.
Specifically what I'm after is float switch attached to a relay that sits in the low voltage power line (12V DC) going to the Nano controller.

I know I can buy this... https://www.saltwateraquarium.com/s...DT2JLaWcU2exfaJOjbICWJgg5rh_ydZ0aAowiEALw_wcB

But I believe I can simply build something that does the same thing, maybe in a different way, for far less than $60.00.
I "should" be able to cut the 12V DC line and use that line to power a relay and pass or shut off current to the Nano controller depending in the realy being open or closed.
The relay, of course, is controlled by the float switch.

I just don't understand: A> what relay to buy and B> how to wire it between the Nano control and the float switch.

Any help anyone can provide is greatly appreciated...

redfishbluefish · Jan 20, 2020

I think THIS LINK will help in setting up an ATO using a rely and two float switches. Simply offset the float switches and wire in series. I've made quite a few.

One more important point.....most float switches are not truly waterproof where the wires enter the switch. That is why the ones I built above are in CPVC pipe, and the switch is drilled and tapped into the end cap. Hope this helps.

DWill · Jan 20, 2020

redfishbluefish said:
I think THIS LINK will help in setting up an ATO using a rely and two float switches. Simply offset the float switches and wire in series. I've made quite a few.

One more important point.....most float switches are not truly waterproof where the wires enter the switch. That is why the ones I built above are in CPVC pipe, and the switch is drilled and tapped into the end cap. Hope this helps.

Thank you...

Joekovar · Jan 23, 2020

redfishbluefish said:

These look like the float switches that have the magnet exposed on the inside of the cylinder. If they're not, where'd you get them? All I can find is ones with partially exposed magnets.

redfishbluefish · Jan 23, 2020

Joekovar said:
These look like the float switches that have the magnet exposed on the inside of the cylinder. If they're not, where'd you get them? All I can find is ones with partially exposed magnets.

My last order was out of China, off of ebay, for one dollar each. That company/link is no longer active. However, looking on ebay, I found similar ones for $1.44 each. Note, I typically order between 5 to 10 each time I order. HERE's the link on ebay. Note, my search on ebay was, "float switch aquarium."

NanoDJS · Jan 23, 2020

https://www.grainger.com/product/6XJH8?gclid=Cj0KCQiApaXxBRDNARIsAGFdaB_QMb3jEzIT2exS7Le8wA58-y3Of-Mhwz4bvsphtsW6ED-wahUFvnoaAkv7EALw_wcB&cm_mmc=PPC:+Google+PLA&ef_id=Cj0KCQiApaXxBRDNARIsAGFdaB_QMb3jEzIT2exS7Le8wA58-y3Of-Mhwz4bvsphtsW6ED-wahUFvnoaAkv7EALw_wcB:G:s&s_kwcid=AL!2966!3!281698275960!!!g!471329001544

wire this into the 12v hot line to break it even has a clamp ! So cut the 12v power and wire this in end to end in line, if the water goes to the top it will cut the 12v. I think this is what your trying to do correct?

Joekovar · Jan 23, 2020

redfishbluefish said:
My last order was out of China, off of ebay, for one dollar each. That company/link is no longer active. However, looking on ebay, I found similar ones for $1.44 each. Note, I typically order between 5 to 10 each time I order. HERE's the link on ebay. Note, my search on ebay was, "float switch aquarium."

Well there's my problem, I wasn't looking at eBay!

pdxmonkeyboy · Jan 24, 2020

Here you go...

DWill · Jan 24, 2020

NanoDJS said:
https://www.grainger.com/product/6XJH8?gclid=Cj0KCQiApaXxBRDNARIsAGFdaB_QMb3jEzIT2exS7Le8wA58-y3Of-Mhwz4bvsphtsW6ED-wahUFvnoaAkv7EALw_wcB&cm_mmc=PPC:+Google+PLA&ef_id=Cj0KCQiApaXxBRDNARIsAGFdaB_QMb3jEzIT2exS7Le8wA58-y3Of-Mhwz4bvsphtsW6ED-wahUFvnoaAkv7EALw_wcB:G:s&s_kwcid=AL!2966!3!281698275960!!!g!471329001544
wire this into the 12v hot line to break it even has a clamp ! So cut the 12v power and wire this in end to end in line, if the water goes to the top it will cut the 12v. I think this is what your trying to do correct?

Yes, I want to cut power to the Tunze pump by cutting the 12V's going to the controller. Doing that will give me a completely independent and redundant backup. I just glanced at this, I'll look at closer in a bit... Thank you...

DWill · Jan 24, 2020

pdxmonkeyboy said:
Here you go...

Perfect... I just need a 12V relay. I think I'm also going to use a optical sensor in place of the float switch.

pdxmonkeyboy · Jan 24, 2020

you can get a relay for like $2 on amazon. Buy some heat shrink tubing as well to make your connections reasonable waterproof. have fun.

NanoDJS · Jan 24, 2020

the relay thing , is totally crazy , he already has the ATO , this is going to be a backup float. Its a 6v pump , so your going to make a 12v power supply and all that ish that can get wet to run a 12 v relay to break a 6v signal ????....... The pan switch will simply cut the 6v pump off if it goes over the float ( plastic on that unit) they are designed to be used for years and years and break mechanically the signal even when the optical fails . The other method is the wrong application and 4 steps to do 1 thing that the switch does . relays are typically used in 24v < control voltage turning on 110v 220v 440v things so we dont burn out switches , its a magnetic switch. Its gonna cost alot more thatn 12 bucks also , whereas the switch is 17 and has a warranty and a child could wire it inline , cut the positvie going to pump from optical float and just wire one side of switch to pump side and other side to the eye side done. it literally goes in line of the 6v positive. The relay would control the pump which he already has all that .